Who was the "greatest" single season home-run hitter of all time?

After our previous piece on how many bombs Mark McGwire might have hit without using steroids, there was a good discussion over who should be considered the "greatest" single-season home-run hitter of all time. If we cross McGwire and his druggie buddies off the list, what about the benefits gained by Babe Ruth, who had only to face pitching of his own color? But then, they also did it without access to the training and nutrition methods available to modern hitters. What about expansion? The increased pool of overseas players?

Let's be honest. There is no "apples to apples" comparison possible, as Flo might say. Can't do it. Not at all. No, sirree. Fuhgedaboutit.

After the jump, of course, that's exactly what we'll be trying to do.

Or, at least, trying to take a couple of wobbly steps down the path, by attempting to filter out a couple of the most obvious road-bumps. Home-run frequency for the era, and number of games played. One of the first things is to appreciate how much more common HRs are these days. Despite the drastic rule modifications that have taken place, you'd be surprised how little the main stats of BA, OBP and SLG have changed over the decades - all three are still within 10% of the figures they were, all the way back in 1871. The graph below plots five: BA (Bordeaux - hey, that's what the spreadsheet calls it!), OBP (Black), SLG (Green), OPS (Dark Violet) and HR per game (Red), for each season from 1871-2009.

But see that red line, rising up like the national debt? [Ooh! Political satire!] That's home-runs per game: more than five times as common as they were in 1871, and over seventeen times as common as they were in 1878, when there were a grand total of...twenty-three long balls. Mark Reynolds had more home-runs before the All-Star break last year, than every major-league hitter combined that season. Only one player hit more home-runs in 1878 than Chris Young had in one game: Paul Hines of the Providence Greys, who led the major-leagues with...four bombs.

This dead-ball era extended, more or less, from the birth of baseball through until 1920 A multitude of reasons go into this. Foul balls were not counted as strikes until the early years of the 20th century, and the graph does show a drop in home-runs around this rule modification. Balls were customarily kept in play for 100 pitches or more, gradually becoming softer and more difficult to hit out. This eventually changed after the 1920 fatal beaning of Roy Thomas, which also led to the banning of the spitball. There were also some insane ballparks, such as the Huntington Avenue Grounds in Boston, where center-field measured 635 feet. On the other hand, at Lakefront Park in Chicago, the distance to the foul poles was only 200 feet.

As an aside, such a lack of power in the game led to one of the more ironic, by modern standards at least, player nicknames in history. Frank Baker, one the best players of the dead-ball era, earned the nickname of "Home Run" Baker for hitting just two home runs in the 1911 World Series. Although he led or tied the American League in home runs four consecutive years, from 1911 to 1914, the most he hit in a season was 12, and he finished with a total of 96 home runs for his career - less than Tim "Not so Home-Run" McCarver.

To describe the methodology, what I did was the take the home-run leader for each season and run a series of adjustments to the raw home-run number posted, to come up with a number I call HR+. Firstly, I compared the number to the home-ruin rate for the year. The baseline was the 2008 season, when the rate was, conveniently, 1.00 home-runs per game. For example, if you hit a home-run when the rate was 0.90. it would be worth 1/0.90 = 1.11 "adjusted" homers. The next adjustment is for number of games in the season. While I has been at least 150 for most of the last century, that hasn't always been the case. The 1871 Philadelphia Athletics won the league by playing only 28 games, so we scale their champion hitter by a factor of 162/28. Finally, we adjust for the park factor, using BR's multi-year hitting number.

Note: this does not mean that Babe Ruth would have hit X home runs in the modern game. It is simply an effort to provide a comparative number, based on his performance relative to the era, adjusting for

The list is dominated by players from the early era, when home-run hitting was, it appears, much harder than it is now. The last player to reach even an HR+ of a hundred, was Jimmie Foxx in 1933, whose 48 home-runs was good for a mark of 115.84. Hank Greenberg came fairly close in 1938 (95.04), and again in 1946 (89.06), but the best number in modern times is Frank Howard's 74.36 for Washington in 1968. That was a season in which pitching dominated - the overall ERA in the National League that year was below three, the only time that has happened since the dead-ball period. For reference, the numbers in some other historic seasons were: Roger Maris (1961), 64.21; Mark McGwire (1999), 56.46; and Barry Bonds (2001), 70.09. Albert Pujols' MLB-leading total from last year has an HR+ of just 45.65.

Babe Ruth has three of the top five HR+ numbers. It's difficult to over-state just how much he dominated the game, but in that 1920 season where he had 54 HR, Ruth hit more long balls by himself, than any other team in the American League. The next most by another other batter that season0 was less than twenty - Ruth had 24 in just May and June. His slugging percentage was more than 217 points higher than the second-placed hitter; as a yardstick, in 2001 Bonds' SLG was "only" 126 point better than the #2 in the league. While Ruth would have seasons where he would hit more home-runs, it's hard to argue that his 1920 campaign was the most impressive of all time. Oh, and he made a spot-start for the Yankees, winning that game on the mound. I think it's safe to say we'll never see a year like that again.

Ruth in the 1920 silent movie, Headin' Home

I should say a bit about some of the other players on the list, in particular, Jim O'Rourke, whose total of six home-runs for the 1875 Boston Red Stockings comes out as the second-best HR+ mark of all-time. That's because O'Rourke, by himself, hit 15% of all home-runs that season. Much like Ruth, ten of the twelve other teams managed less in total, than O'Rourke did alone. Hell, six teams hit no balls out at all, including the St. Louis Browns who played 68 games that year. I'm not sure there has ever been a team more dominant than the Boston one on which O'Rourke played. They posted a record of 71-8, pitched to glory by future HoFer Al Spalding - yes, he of the sporting goods store. Spalding  started 63 games, came out of the bullpen in nine more, and went 55-5, with eight saves.

Anyway, back to O'Rourke. Despite his homer prowess, he didn't lead his team in OPS or even SLG. He finished fifth in both categories, which went to Cal McVey's .355/.356/.517 - McVey only had three home-runs, but his 36 doubles were almost three times O'Rourke's. Jim did, however, lead the team in walks - with nine. He played mostly the outfield, but also saw duty at 1B, 3B, and even as catcher. O'Rourke's career continued until 1893, then, after a hiatus, with a last hurrah in 1904; at the age of 54, he became the oldest man to hit safely in major-league history. Known as "Orator Jim" because of his law degree, according to his grandson, he "confused the heck out of umpires when he challenged a call. The umpire went all to pieces because he couldn’t understand what [Jim] was saying."

Charley Jones, #4 on the list, is perhaps most notable because there's no record of his death. [I assume it happened, as otherwise he's be 150 in April.] During the 1879 season, the top two career home-run hitters were on the same team - Jones and Lip Pike, more of whom later. That has only happened twice since, the last time being in 1934 when Ruth and Lou Gehrig were with the Yankees. Jones was the first player to hit two home-runs in one inning (on June 10, 1880), but lost the subsequent two seasons, being blacklisted as the result of a dispute over salary payment. Charley was also a professional model and the clothes he accumulated as a result, led to him being called "The Knight of the Limitless Linen." They don't have nicknames like that any more.

Lip Pike was the first famous Jewish ballplayer, and - entirely coincidentally - the first to be openly recognized as a professional. He was also renowned for his speed - in August 1873, he beat a trotting horse called Clarence in a 100-yard race, posting a time of 10 seconds flat to win $250. Despite being slightly-built by modern standards - at 5'8" and 158 lbs, he was about Augie-sized - the distance of his home-runs was a source of wonder at the time. One travelled 360 feet, hitting a metal bar on top of a pagoda, 40 feet off the ground at that point, with enough force to bend it. Before the formalization of the sport, it's recorded he hit six home-runs during a single game in July 1866, though in those days the game resembled slow-pitch softball more than the sport we know now.

Ned Williamson and Fred Pfeiffer must have possessed a time-machine, and traveled forward to the late 1990s to acquire some PEDs. For how else to explain their 1884 season? Williamson's 27 homers was three times as many as any other campaign. Indeed, in the rest of his twelve season career, he only hit 37. Similarly, Pfeiffer's 25 was far and away his best: only one other time did he have more than eight. But it wasn't just them. That year's Cubs boasted seven of the league's top ten home-run tallies, and the team as a whole were responsible for 44% of all long-balls hit in the NL. There is a very good reason: Lake Front Park.

As noted, it was extremely short down the lines, and for most of the time the Cubs played there, the ground rules declared that balls hit over the fence down the line were only scored as doubles, regardless of distance. In left-center and right-center were two additional poles, and to get credit for a home-run, the ball had to go between them, where the distance was more respectable. In 1884, however, that rule was abandoned. As a result the team doubles total dropped from 277 to 162, while homers almost eleven-fold, from 13 to 142! The resulting park factor of 109, is comparable to Coors Field last season. Only two of Williamson's 27 blasts came on the road, but his single-season mark would stand for 35 years, until the Babe surpassed it in 1919.

Finally, there's Gavvy Cravath - born Clifford Cravath, the name "Gavvy" was allegedly given to him in his days playing in the PCL, after he hit a ball that killed a seagull - "gaviota" in Spanish - in flight. [On this basis, I anoint the Big Unit as "Pally" Johnson, since a dove is "paloma"] He was a mine of marvellous lines, such as "I steal bases with my bat," or "There is no advice I can give in batting, except to hammer the ball." But he still cultivated a talent for hitting to the opposite field: while in Minneapolis, he allegedly shattered the same nearby store window, three times in a single week. That skill also served him well in his time with Philadelphia, whose right-field line measured only 272 feet, leading to his 1915 season - 19 of his 24 homers came at home. In the World Series that year, the opposing Phillies respected his power so much, they didn't pitch their young left-hander. That was some guy called Babe Ruth.

I have to say, I really enjoyed writing this piece. Not so much for the number-crunching - though you know me, when I die, I expect my gravestone to show a Win Probability chart for my life (ending at 0%, naturally). No, it was digging up the historical trivia on the old-timers that was fascinating, and I want to give particular credit to the fabulous SABR Baseball Biography Project, which is a great resource and a great waste of time.  I'll close with another quote from Cravath, which seems a fitting way to end this celebration of some sluggers from yesteryear:

"I do not claim to be the fastest man in the world, but I can get around the bases with a fair wind and all sails set. And so long as I am busting the old apple on the seam, I am not worrying a great deal about my legs."
   -- Gavvy Cravath